/*公共样式*/
*{margin: 0;padding: 0;}
ul,li{list-style: none;}
img{display: block;}
html,body{height: 100%;}
.clearfix:after{content:"";display: block;clear: both;}

#main{height: 100%;display: flex;flex-direction: column;}
#content{flex:1;overflow: auto;margin-bottom: 50px;position: relative;display: flex;flex-direction: column;}